1. Field of the Invention
The present invention relates to a driving circuit for a liquid-crystal display device which is integrated on a liquid-crystal display panel of an active matrix type on which pixels (liquid-crystal display elements), arranged in rows and columns, function to store data.
2. Description of the Prior Art
A liquid-crystal display device of the active matrix type is capable of providing a display quality as high as that of a CRT display device equipped with a cathode-ray tube, and is hence attractive as a replacement of CRT display devices.
The liquid-crystal display device needs a driving circuit which drives data lines or scanning lines. A liquid-crystal display device of the active matrix type in which the driving circuit is integrated on a liquid-crystal display panel thereof has become in practical use. For example, such a liquid-crystal display device is used for a view finder of a video camera.
The liquid-crystal display device having the driving circuit integrated on the liquid-crystal display panel is superior, in terms of device miniaturization, feature size reduction and cost reduction, to a liquid-crystal display device in which the driving circuit is externally mounted on the liquid-crystal display panel by means of a mounting process, such as a TAB (Tape Automated Bonding) scheme or a COG (Chip On Glass) scheme.
In this regard, recently, it has been strongly desired that a liquid-crystal display device of the active matrix type in which the driving circuit is integrated on the liquid-crystal display panel becomes in practical use as a display device of information terminal equipment. A liquid-crystal display device of the active matrix type which has been practically used has a display area as small as approximately one inch. Hence, the driving circuit for driving display elements arrayed in the display area may be small and a probability that a defect occurs in the driving circuit is low.
In the meantime, it is required that the liquid-crystal display device of the active matrix type for use in information terminal equipment is equipped with a large display area. Hence, a large size driving circuit is needed to drive display elements arrayed in such a large display area and a probability that a defect occurs in the driving circuit is high.
If a defect occurs in the driving circuit integrated on the display panel of the liquid-crystal display device of the active matrix type, the liquid-crystal display device itself including the liquid-crystal display panel, is considered as a defective device. Hence, it is required that the driving circuit be designed to easily avoid a defect that occurs therein and enable continuous use rather than operating as a defective device.